Processing of superfine WC powders into high quality WC/Co materials

摘要

Milling ocnditions were identified to vacuum sinter a superfine WC powder into a high quality WC/Co material with an average grain size of 0.2 #um#m,minimal A-type porosity and no discontinuous grain growth.The solids loading,milling time,dispersant addition and cobalt particle size wee varied during milling to produced the high quality WC/Co sintered material.Optimum microstructures were obtained when the milling process provided a homogeneous distribution of cobalt throughout the formulated powder.The most effective way to obtain this distribution was through the use of a fine 0.4 #um#m cobalt powder n combination with a non-ionic dispersant.Without the dispersant,the milling time had to be extended at the high solids loading due to an increased slip viscosity.For a coarser 1.1 #um#m Co powder,longer milling time and lower solids content were needed to distribute the cobalt binder throughout the superfine WC/Co formulation.